microSD && ext3 file system

Matthias Apitz guru at unixarea.de
Mon Apr 2 19:52:40 CEST 2012


After some hours of testing I'm now totally lost with creating an ext3
file system on a (new) 4GB micro SD card.

Using my FR (running SHR) I created one new partition on the SD with
fdisk(1) and it looks like this:

root at om-gta02 ~ # fdisk -l /dev/mmcblk0

Disk /dev/mmcblk0: 3953 MB, 3953131520 bytes
4 heads, 16 sectors/track, 120640 cylinders
Units = cylinders of 64 * 512 = 32768 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
Disk identifier: 0x0aecb0ac

        Device Boot      Start         End      Blocks   Id  System
/dev/mmcblk0p1               1      120640     3860472   83  Linux

Then I created the ext3 file system on it with:

root at om-gta02 ~ # mkfs.ext3 /dev/mmcblk0p1
mke2fs 1.41.9 (22-Aug-2009)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
241440 inodes, 965118 blocks
48255 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=989855744
30 block groups
32768 blocks per group, 32768 fragments per group
8048 inodes per group
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736

Writing inode tables: done                            
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 32 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

now mounting against the /etc/fstab line failes:

root at om-gta02 ~ # mount /media/card
mount: wrong fs type, bad option, bad superblock on /dev/mmcblk0p1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

mounting with "-t ext3" works and after this as well mounting with the
normal line in fstab(5) works too:

root at om-gta02 ~ # mount -t ext3 /dev/mmcblk0p1 /media/card
root at om-gta02 ~ # umount /media/card
root at om-gta02 ~ # mount /media/card
root at om-gta02 ~ # 

and it is really mounted:

root at om-gta02 ~ # mount
/dev/mmcblk0p1 on /media/card type ext3 (rw,errors=continue,data=ordered)

now I create a dir and copy over some files from the host connected via

root at om-gta02 ~ # mkdir /media/card/dic


$ scp -rp stardict-duden-2.4.2 root at miko:/media/card/dic
duden.ifo                                     100%  155     0.2KB/s   00:00    
duden.idx                                     100% 2360KB 786.7KB/s   00:03    
duden.dict.dz                                 100% 6719KB 559.9KB/s   00:12    
scp: /media/card/dic/stardict-duden-2.4.2/duden.dict.dz: Read-only file system
scp: /media/card/dic/stardict-duden-2.4.2/duden.idx.oft: Read-only file system
scp: /media/card/dic/stardict-duden-2.4.2/duden(2).idx.oft: Read-only file system

the SCP fails and magically now the SD in the FR is mounted read-only:

root at om-gta02 ~ # mount
/dev/mmcblk0p1 on /media/card type ext3 (ro,errors=continue,data=ordered)

What is wrong or what do I wrong with this SD card?

Matthias Apitz
e <guru at unixarea.de> - w http://www.unixarea.de/
UNIX since V7 on PDP-11, UNIX on mainframe since ESER 1055 (IBM /370)
UNIX on x86 since SVR4.2 UnixWare 2.1.2, FreeBSD since 2.2.5

More information about the community mailing list